Hydrodynamic Bearing Pressure Equalization Notch

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Solution Overview

Problem

Hydrodynamic bearing devices with open ends face challenges in preventing lubricant leakage and air bubble infiltration, especially during assembly or installation, due to accidental blockage by fingers or tools, which can lead to lubricant loss and motor failure.

Innovation Solution

The hydrodynamic bearing device incorporates a communication mechanism, such as notches or communication holes, on the annular protrusions to maintain pressure equality between inner and outer spaces, preventing pressure transmission to the lubricant and thus preventing leakage and bubble infiltration, even if one end is blocked.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a hydrodynamic bearing has open ends to facilitate assembly and lubrication, then ease of manufacture and operation are improved, but lubricant leakage and air bubble infiltration occur due to accidental blockage

Engineering Contradiction:

Improveease of assemblyVSAvoidlubricant sealing

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The bearing structure is divided into multiple sealed compartments (first bearing chamber and second bearing chamber) separated by a partition wall. Each chamber has its own seal structure, so if one chamber is accidentally blocked during assembly, the other chamber remains sealed and functional, preventing complete bearing failure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A seal structure is introduced as an intermediary element between the bearing chamber and the external environment. This seal structure includes a seal member that contacts the shaft and a seal case that forms a closed chamber, preventing direct communication between the lubricant and external blockages.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If seal structures are added to prevent lubricant leakage, then lubricant sealing is improved, but device complexity increases

Engineering Contradiction:

Improvelubricant sealingVSAvoidseal structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The seal structure is merged with the bearing chamber structure. The seal case forms an integral part of the bearing chamber, and the seal member is positioned within the same assembly, reducing the number of separate components and simplifying manufacturing while maintaining sealing effectiveness.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The seal structure serves multiple functions: it seals the lubricant within the bearing chamber, prevents air bubble infiltration, and provides a barrier against accidental blockages during assembly. This multi-functionality reduces the need for additional separate protective structures.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Loss of substance

If the bearing is sealed to prevent lubricant loss, then lubricant retention is improved, but pressure buildup occurs when openings are accidentally blocked

Engineering Contradiction:

Improvelubricant retentionVSAvoidinternal pressure

Core Design Contradiction:

Loss of substanceVSStress or pressure

Solution Approach 1:

The bearing is divided into multiple sealed chambers that are isolated from each other by a partition wall. If one chamber is accidentally blocked during assembly, the pressure buildup is confined to that single chamber while other chambers remain at normal pressure, preventing catastrophic pressure-related failures.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The partition wall acts as a pre-established pressure buffer. By dividing the bearing into separate chambers before assembly begins, the design anticipates and cushions against the harmful effects of accidental blockages, allowing the system to tolerate assembly errors without pressure-related damage.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution effectively prevents lubricant leakage and air bubble infiltration, ensuring reliable operation and extended bearing life by maintaining pressure balance and isolating the lubricant from external pressures.

Implementation Method 1

a dynamic pressure generation groove that is formed around the outer peripheral face of the shaft or the inner peripheral face of the sleeve and that supports the sleeve rotatably with respect to the shaft

Methodology Applied

Scientific EffectHydrodynamic pressure generation: Hydrodynamic Cavitation

Implementation Method 2

The bearing component includes a lubricant that fills the space between the shaft and the sleeve

Methodology Applied

Scientific EffectLubrication: Lubrication

Data Source

PatentUS7654742B2Hydrodynamic bearing device, motor, recording disc driving apparatus and assembly jig

Publication Date: 2010.02.02 PHC HLDG CORP

AI summary

A hydrodynamic bearing device 4 comprises a shaft 41, a second thrust flange 41c, a sleeve 42, a radial bearing 71, and a thrust bearing 73. The second thrust flange 41c is fixed near one end of the shaft 41. A third cylindrical protrusion 42e that protrudes farther in the axial direction than the second thrust flange is fixed to or integrally machined at one end of the sleeve 42. A notch 50 that communicates between a radial inner space and a radial outer space separated by the third cylindrical protrusion 42e is provided to the third cylindrical protrusion 42e.